A sludge pit is commonly employed to collect paint wastes and residues generated in wet spray booth operations. Such operations are common, for example, in the automotive industry, and the sludge which accumulates is collected in a sludge pit or sludge consolidation equipment in the form of a liquid/solid, semi-solid or solid mass. The sludge is comprised of various liquid and particulate materials, including pigments, dyes, paint vehicles, paint detackifiers, and the like. As described in the aforementioned co-pending application, water typically is present, but the amount can vary depending on the nature of the particular operations being carried out. Periodically, usually annually or semi-annually, a sludge pit must be cleaned out and the sludge removed for environmentally acceptable disposal elsewhere. Most states require removed sludge to be processed as hazardous waste.
Sludge removal has heretofore been conventionally accomplished by known floating, sinking or dispersion and pumping methods. In all such methods, the accumulated sludge, after aging, has become hardened and difficult to remove. For example, percussive equipment (i.e., jack hammers, or the like) frequently must be employed to break up and remove the hardened sludge solids. Even after such removal, the solids present further problems of handling and disposal. Clean out of sludge pits thus is expensive, time consuming and potentially hazardous.
There thus exists a need for new and improved techniques for sludge removal and waste handling.